Re: [Exim] Canonicalizing Addresses

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Author: Vadim Vygonets
Date:  
To: Exim List
Subject: Re: [Exim] Canonicalizing Addresses
Quoth Philip Hazel on Wed, Sep 15, 1999:
> On Tue, 14 Sep 1999, Vadim Vygonets wrote:
> > And when these domains do appear, you just have to hope that your
> > users won't send mail there, or it will arrive to the xxx.ch
> > subdomain of cam.ac.uk.
>
> Oh, absolutely. We went round several circles arguing this recently, and
> concluded that there was nothing we could do to improve matters.


I think that educating your users about the whole issue of e-mail
addresses is the way to go. I'm trying to encourage our users to
write local e-mail addresses either as "user@???" or as
"user", but not as "user@cs". We do have a rewrite rule for
that, but it just doesn't feel right. And when you omit the
domain name completely, most mailers beautify it with the correct
GECOS[0].

> > And, of course, we had a user sending mail to something.md when
> > he meant something.md.huji.ac.il when the domain something.md
> > appeared...
>
> As soon as we realized, we stopped issuing internal domains consisting
> of only two letters, to minimize the risk. (The existing two letter ones
> to back to the days before we were connected to the Internet.)


If your users are really lazy, one option is to educate them to
say "user@???" and translate /cam$/ into "cam.ac.uk".
In any case, I think that user education is a part of the
solution.

It also seems to me that Sendmail used gethostbyname(3) or
something. Our domain search path used to contain all parent
domains, so mail sent to <user@???> arrived to
<user@???>. Which resulted in someone having
"user@???." in his .forward file, which, in turn, resulted in
strip_trailing_dot in both mailserver and client configuration.

Vadik.

[0] When you meet a person and want to ask what his name is, you
    usually ask for his e-mail address and proceed from there[1].
    When you really must know the person's name, you should ask,
    "what's your GECOS?".  I think I should write an essay about
    modern UNIX hackers' etiquette.


[1] It doesn't have all kind of social strings attached.  It's
    not a proper introduction.  Most people feel uneasy when they
    forget other person's name (as it's against the laws of the
    etiquette); forgetting e-mail addresses is acceptable.


--
Do not meddle in the affairs of troff, for it is subtle and quick
to anger.